In recent years the public has become very aware of the importance of X-ray examination of women's breasts in the control and cure of breast cancer. The early detection of cancerous tumors is recognized as significantly improving the chances of successful treatment. As a consequence, women of a certain age or genealogical background are subject to X-ray examination of their breasts at frequent intervals. Such examination often detects tumors or lesions which are of a questionable character, it being impossible to determine from the X-ray whether the tumor or lesion is malignant or benign. In such situations, it is normal to take a specimen or biopsy of the tumor or lesion to permit a careful examination of the abnormal tissue.
The most common means of taking a biopsy of a tumor or lesion in a woman's breast is by using an elongated needle which may be inserted with a rotary movement to cut a core sample of tissue in the area of the tumor or lesion. The needle is equipped with suction means to aid in extracting the cylindrical section of tissue. Since the current trend is toward early detection through frequent examination, the tumor or lesion which is to be checked through the biopsy is often very small and barely discernable on the X-ray. With the tumor or lesion often being well below the skin surface, it is extremely difficult to insert the biopsy needle with sufficient accuracy to engage and sample the area of tissue that is of interest and requires further testing.
In the presently used procedure, the breast of the patient is compressed against a horizontal surface below which the X-ray film is positioned. The compressing member is placed above the breast, clamping it against the surface, leaving a panel of skin exposed through a rectangular opening which has indicia on the sides of the opening to aid in establishing the location of the tumor discovered on the X-ray. By establishing the coordinates of the location of the tumor from the X-ray, a mark is placed on the location on the exposed skin using the indicia beside the opening to show where the biopsy needle should be inserted. An additional X-ray is taken to show the depth of the tumor so that the needle may be inserted and the specimen taken at the proper depth below the skin surface. After a biopsy specimen has been taken, another X-ray is taken to assure that the biopsy specimen is from the suspected tissue.
Because of the limited size of the tissue to be sampled and the possible errors in correlating the location of the needle insertion with the location of the tumor as shown on the X-ray, it is not unusual for many needle insertions to be required before achieving the proper location of the needle with respect to the tumor. The procedure causes considerable pain and discomfort and the prolongation resulting from the techniques employed suggest that improved techniques are required.
One attempt at locating the biopsy needle more precisely with respect to an X-ray picture of a tumor has involved the use of movable cross wires to create a shadow produced by an incandescent lamp to locate the needle insertion point on the skin. This technique has not proven to be particularly helpful, since the shadow image of the wires was not sharp enough to give a precise location and the normal ambient light in the area was usually too high to permit good visibility of the shadow image of the wires.
Another approach involved use of a laser dot which was projected in from the side to spot the needle insertion location on the skin. The angle at which the laser beam was projected tended to introduce errors since any deflection of the skin would cause the laser spot to shift location.
Another problem associated with the biopsy is the difficulty of inserting the needle in a direction perpendicular to the horizontal support surface. The selected location on the skin is intended to be directly over the tumor, so the needle must be inserted vertically if it is to engage the tumor. However, the biopsy needle is designed to be rotated as it is inserted. Otherwise, the sharp angled end on the needle will tend to deflect the path of the needle to one side as it is inserted. Experience has revealed that it is very difficult to rotate the biopsy needle and maintain its vertical orientation as it is inserted. Accordingly, it would be desirable to provide means for locating the insertion point for a biopsy needle and for guiding the needle to maintain its vertical position as it is inserted.